Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net loss	$ (21,598)	$ (35,712)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	419	344
Amortization of premium/discount on investments	(60)	(274)
Non-cash interest expense	192	99
Stock-based compensation expense	3,191	2,261
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	272	(4,492)
Right-of-use asset	458	699
Accounts payable and accrued liabilities	(1,276)	5,596
Deferred revenue	57,058	2,069
Lease liabilities	777	(265)
Net cash provided by (used in) operating activities	39,433	(29,675)
Investing activities
Purchases of property and equipment	(314)	(335)
Purchase of short-term investments	(4,967)	(54,306)
Maturities of short-term investments	29,311	65,625
Proceeds from the sale of short-term investments	0	1,391
Net cash provided by investing activities	24,030	12,375
Financing activities
Proceeds from borrowings, net of issuance costs	5,000	1,977
Proceeds from sale of common stock and warrants, net of offering costs	56,271	23,598
Repayment of debt	0	(1,333)
Proceeds from exercise of stock options	121	13
Net cash provided by financing activities	61,392	24,255
Effect of exchange rate on cash, cash equivalents and restricted cash	(35)	(17)
Net increase in cash and cash equivalents and restricted cash	124,820	6,938
Cash and cash equivalents and restricted cash, beginning of period	16,509	10,843
Cash and cash equivalents and restricted cash, end of period	141,329	17,781
Supplemental Information
Discount in connection with issuance of debt	335	0
Cash paid for interest	345	97
Recognition of right-of-use asset	$ 0	$ 11,667